Expansion joints, generally speaking, is a crowded art with many patents having been granted particularly in the area of expansion and contraction of concrete slabs where the joint between the slabs expands in response to contraction of a drying slab. Where tiles, stucco or plaster are laid up on a substrate such as a concrete slab or a wall movement of the substrate and/or the tiles creates a situation where there can be cracking or separation in the floor or wall.
In the case of tiles these are quite often ceramic tiles. The substrate and/or the tiles may move due to expansion and/or contraction. It is desirable to provide expansion joints in the form of divider strips that allow for this movement.
It is conventional practice to form expansion joints in tiling floors where simple strips of angle are placed side by side with one flange adhered horizontally to the substrate and the other flange at 90 degrees is upright. Tiles are applied over the horizontal flange up to the vertical upright flange. A caulking or other flexible seal is applied to the gap between the vertical flanges of the space strips. Over time there can be unsightly separation of the tiles or the seal from the strip. This creates gaps where debris can accumulate. In food areas, food particles can accumulate in these gaps, liquids can pass through and under the tiles. Reparation and repair costs can be high as whole sections of tiles may have to be removed and replaced which can change the whole look of a tile section in say a shopping mall where wear and tear on the surrounding tiles that remain, compared to the newer replaced tiles, can be detrimental to the whole look of the flooring in what is otherwise intended to be a desirable sales environment. This can generate complaints from store owners and tenants and there is also the inconvenience of having the tiles relaid.
The present applicant has conducted a search post invention in order to see just what kinds of expansion joints have been used in relation to ceramic tiles or other layered arrangements where these layered arrangements are layered up on a substrate and has found the following:—                U.S. Pat. No. 3,903,587;        U.S. Pat. No. 5,263,294;        U.S. Pat. No. 5,333,432;        U.S. Pat. No. 9,062,453;        U.S. Pat. No. 4,651,488;        EP0165611;        GB2278134B;        US20010017015A1;        GB1485950A;        DE202010015513;        DE19753937C1.        
Inclusion of these documents is post the present invention but the contents of these patent specifications are incorporated herein by cross-reference in their entirety and the reader hereof should consult these documents in as far as they may assist in further understanding or application of the present invention. These also demonstrate examples as to where the present invention might be applied although these are considered non limiting situations.
Outline
In one aspect the present invention resides in an expansion joint applied to a layer applied to a substrate, the joint having a first strip extending on one side of the joint and a second strip extending on the other side of the joint, an upper surface plate of the first strip being adapted to extend across the joint, and being disposed to move across the joint, the strips being mutually aligned for relative movement while maintaining the upper surface of the first strip in a predetermined plane relative to the second strip.
Preferably, the first and second strips comprise mutually aligned male and female co-operating parts. Typically the female part carries the upper surface plate. The female part preferably comprises a channel extending along the strip. The parts may both be made from metal or a suitable plastics. Another arrangement might involve one part plastics and one part metal.
Preferably, the joint includes one or more seals between the strips. The seals may be integrally formed as part of the strip. Typically one or both stripos have seal receiving slots or other formations adapted to retain a separate seal in a specific position.
In one embodiment there is provided a groove or channel holding a seal strip. In another embodiment there is provided a rebate holding a seal strip. In another embodiment a seal may be formed in a contact surface of one or both parts. Preferably, a seal may be formed in of a mutual contact surface of a plastics male part. Preferably, upper and lower seals are employed, the upper seal being disposed along an edge of the surface plate to move with it and seal the surface plate to the second strip. The lower seal typically moves with the second strip and seals the second strip to the first strip. Typically the lower seal is secured to an edge of the male part and seals the male part to the female part. In the case of upper and lower seals the strips typically include edge rebates serving to retain the seals in place, the edge rebates being formed along the strips to bias the seals to secure positions. The rebates may taper and typically be dovetailed. These rebates may be dovetail end portions of the respective parts and may be fitted with correspondingly dovetailed resilient strips to provide the seal.
In another embodiment a seal may be provided by the male part may having a marginal edge region which has marginal surface regions which are roughened, knurled or ribbed to provide a seal. This is more preferably provided in a plastics male part.
In another embodiment a terminal edge of the male part may have spacer to hold it spaced from an endwall of the female part. The spacer may comprise a projecting flange. This flange may be resilient, weakened or frangible. The flange may be set at 90 degrees or at an angle.